"It sees the word 'bomb' and knows that there's a difference between 'bomb' as in failure, or 'the bomb' as in good," said Bill Bickford, vice president of operations at Jacksonville, Fla.-based IxReveal, a company that produces the data-mining software uReveal.

Bickford told Discovery News that the software searches for spikes in activity around specific concepts. When it sees something that looks important, it will flag it so a person can investigate further and decide if it's a threat. A self-described terrorist in South America writing Facebook rants may not be as important as a buzz of activity on a militia site in North Carolina, where the convention is being held. UReveal is designed to distinguish between both.

Another technology, which the Houston-based BRS Labs cannot confirm nor deny whether it is in fact being used at Charlotte's DNC—though it was used at the RNC in Tampa and several other cities—is a special software that takes into account what a scene looks like over several days, then send an alert when any unusual activity registers.

"So it will say this area looks like this most of the time and this other area looks like that," said David Gerulski, vice president of marketing. When that area of the image changes it will send an alert that something has changed.

"A guy standing at the edge of a parking lot for 30 minutes would get flagged," he said. In one sense, it does exactly what police are supposed to do — look for something unusual.

Essentially, it does what police ought to do: scan a zone for suspicious activity.

So far, the conventions have gone on without incident. So, that's good. [DiscoveryNews]